To get your analog guitars sound into the computer which is digital you'll need an audio interface.

Going in needs an A>D conversion, then when it comes out of the computer to some monitors it does a D>A conversion.

There are some really cheap ones maybe that call themselves a 'cable'.

Most windows machines already have a sound card. I plugged into the aux or mic and recorded when I was learning how to record. If you want to hear yourself in real time with the sound from the plugin then you definitely need a low latency interface. (pretty much any modern one is low latency)

I'm not really up on the products, just have to shop and compare and read reviews etc.